This invention is related to the broad field of hydrocarbon conversion. The invention may also broadly be considered to be related to a process for the production of white oils from a feedstock originating from an integrated hydrocarbon conversion process. More specifically, the process relates to the production of white oils by hydrogenating a heavy hydrocarbon feedstock possessing hydrogenatable components to produce naphthenes. The hydrogenation process utilizes as feedstock the heavy hydrogenatable by-product stream of an aromatic alkylation process. The by-product stream is preferably the result of the alkylation of benzene with a hydrocarbon process stream comprising linear olefins which have previously undergone a dehydrogenation step and selective hydrogenation step. The improvement is achieved through the upgrading of the heavy hydrogenatable by-product stream of an aromatic alkylation reaction into a more valuable white oil product which comprises a substantial amount of mono-cyclic naphthenes. Additionally, the white oil product quality may be improved by first selectively hydrogenating diolefins contained in the olefin-containing hydrocarbon feed to the alkylation reaction zone of this process.